There has been known a library apparatus which includes a plurality of storage media, such as magnetic tapes, a plurality of drives, and a library control unit for controlling the drives and which stores a large amount of data and provides the data when the data is used. This library apparatus mounts a predetermined storage medium on a drive in response to a request from a higher-level apparatus, such as a host computer, and reads/writes data from/to the mounted storage medium in accordance with an instruction from the higher-level apparatus.
Japanese Laid-open Patent Publication Nos. 2006-139635 and 2007-310618 are examples of related art.
Such library apparatuses are often used for long-term (several years or decades) external storage of data. Since needs for larger capacity and higher access speed accompany an increase in the amount of stored data for save and extension of time to provide data, storage medium specifications, such as a tape format, are often extended. Accordingly, the life of a storage medium tends to become shorter. For example, regarding backward compatibility of tape drives, the compatibility across generations of storage media is often limited such that reading and writing can be performed on older first generation tapes, only reading can be performed on older second generation tapes, and each of reading and writing cannot be performed on older third generation tapes and tapes older than the older third generation tapes.
Therefore, a user who wants to store data for a long term has to periodically shift the generations of storage media. Transfer of data stored in a storage medium to a new storage medium places large burdens on human resources, facility resources, and time resources for the transfer. In addition, it is preferably to ensure the consistency between management information for volumes indicating the contents of backup storage media and data stored in actual storage media. Furthermore, in order to introduce a new standard storage medium and introduce a new standard drive, it is preferably to update a relation among storage media and drives and to manage the relation.